This application claims the priority of Korean Patent Application No. 2002-51489, filed on Aug. 29, 2002, which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to a projection system, and more particularly, to a projection system employing a scrolling system including two light sources and two light valves.
2. Description of the Related Art
Projection systems are divided into a single-plate type and a tri-plate type depending on a number of light valves. The light valves perform an on/off control of a light emitted from a high-power lamp light source in units of pixels in order to form an image. The single-plate type projection systems render an optical system smaller than the tri-plate type projection systems. However, because the single-plate type projection systems divide white light into red, green, and blue (RGB) light beams using a sequential method, a corresponding optical efficiency is only ⅓ of the optical efficiency of the tri-plate type projection systems. Accordingly, in order to increase the optical efficiency of single-plate type projection systems, approaches for increasing the number light sources have been suggested, such as the one disclosed in U.S. Pat. No. 6,147,720, which describes to a projection system employing two lamps and a single light valve, as shown in FIG. 1.
Referring to FIG. 1, the conventional projection system 10 includes two lamps L1 and L2, which are oriented at 90 degrees to each other, and a filter wheel W, which is oriented at 45 degrees. The two lamps L1 and L2 direct converging input light beams IB1 and IB2, respectively, to a focus at a common spot 12 at one side of the filter wheel W.
Each of the lamps L1 and L2 includes a bulb 14, a reflector 16, and a focusing lens 18. A beam annular portion 20 of the filter wheel W is alternatively used for transmission of the light from the lamp L1 and of a reflection of the input light from the lamp L2 to form a multiplexed light beam MB illuminating a light valve LV. The light valve LV modulates the multiplexed light. beam MB to travel toward a projection lens 24. The projection lens 24 projects the modulated beam onto a screen 26 to form the image.
A video signal is received at a light valve control circuit 28 and applied to the light valve LV via a line 30. A hub motor control circuit 32 controls a rotational speed and a phase of a hub motor 22 installed at the filter wheel W in response to the video signal applied thereto via a line 34 from the light valve control circuit 28. The lamps L1 and L2 are alternately energized from a lamp power supply 36 via lines 40 and 38, respectively. A line 42 is provided via which a signal is provided from the light valve control circuit 28 to the lamp power supply 36. A connection line 44 is provided between the lamp power supply 36 and the hub motor control circuit 42.
This conventional projection system employs two lamps L1 and L2 in order to improve light emission efficiency. However, because the filter wheel W partially transmits the light, the light emission efficiency is not notably improved. Moreover, the conventional projection system is disadvantageous in that it is difficult to achieve a color balance and a wide color gamut
The present invention provides a projection system improving a light emission efficiency and a color balance of a display and expanding a color gamut.
Additional aspects and/or and advantages of the invention will be set forth in part in the description which follows, and, in part, will be obvious from the description, or may be learned by practice of the invention.
According to an aspect of the present invention, there is provided a projection system to display an image on a screen, including first and second light sources, separated by a predetermined distance from each other and radiating a single white light in parallel and in the same direction; first and second spiral lens discs including cylindrical lens cells arranged in a spiral shape and separating the single white light incident from the first and second light sources into a multi white light by converting a rotational motion of the cylindrical lens cells into a rectilinear movement of a cylindrical lens array; first and second spectroscopes separating the multi white light incident from the first and second spiral lens discs into color light beams having different wavelength bands; first and second light valves modulating the color light beams incident from the first and second spectroscopes according to an image signal to form the image; and first and second projection lenses projecting the color light beams modulated by the first and second light valves onto the screen to display the image.
According to an aspect of the present invention, the projection system further includes a first fly-eye lens on a first optical path between the first spectroscope and the first light valve; a second fly-eye lens on a second optical path between the second spectroscope and the second light valve, a first relay lens on a third optical path between the first fly-eye lens and the first light valve; and a second relay lens on a fourth optical path between the second fly-eye lens and the second light valve, wherein the first and second relay lenses focus the incident light onto the first and second light valves, respectively.
According to an aspect of the present invention, the projection system further includes a first beam splitter disposed on a fifth optical path between the first relay lens and the first light valve, transmitting the light incident from the first relay lens to the first light valve, and reflecting the light incident from the first light valve to the first projection lens; and a second beam splitter disposed on a sixth optical path between the second relay lens and the second light valve, transmitting the light incident from the second relay lens to the second light valve, and reflecting the light incident from the second light valve to the second projection lens.
According to an aspect of the present invention, the first and second spectroscopes are dichroic filter arrays separating the incident light into the color light beams, and at least one of the dichroic filter arrays comprises dichroic filters to separate the incident light into red, green, and blue light beams or dichroic filters to separate the incident light into yellow, cyan, and magenta light beams.
According to an aspect of the present invention, a color bar in which three colors are included three segments, is formed on each of the first and second light valves.
According to another aspect of the present invention, there is provided a projection system to display an image on a screen, including first and second light sources separated by a predetermined distance from each other and radiating a single white light in parallel and in opposite directions facing each other; first and second spiral lens discs including cylindrical lens cells arranged in a spiral shape and separating the single white light b b from the first and second light sources into a multi light by converting a rotational motion of the cylindrical lens cells into a rectilinear movement of a cylindrical lens array; first and second spectroscopes separating the multi white light incident from the first and second spiral lens discs into color light beams having different wavelengths; a light valve modulating the color light beams incident from the first and second spectroscopes according to an image signal to form the image; and a projection lens, projecting the color light beams modulated by the light valve onto the screen to display the image.
According to an aspect of the present invention, the projection system further includes a first fly-eye lens on a first optical path between the first spectroscope and the light valve; and a second fly-eye lens on a second optical path between the second spectroscope and the light valve.
According to an aspect of the present invention, the projection system further includes a first relay lens on a third optical path between the first fly-eye lens and the light valve; and a second relay lens on a fourth optical path between-the second fly-eye lens and the fight valve, wherein the first and second relay lenses focus the incident light onto the light valve.
According to an aspect of the present invention, the projection system further includes a first beam splitter disposed on a fifth optical path between the first relay lens and the light valve, transmitting the light incident from the first relay lens to the light valve, and reflecting the light incident from the light valve to the projection lens; and a second beam splitter, disposed on a sixth optical path between the second relay lens and the light valve, transmitting the light incident from the second relay lens to the light valve, and reflecting the light incident from the light valve to the projection lens.
According to an aspect of the present invention, the first and second spectroscopes are dichroic filter arrays, to separate the incident light into the color light beams, and at least one of the dichroic filter arrays includes a dichroic filter to separate the incident light into red, green, and blue light beams or dichroic filters to separate the incident light into yellow, cyan, and magenta light beams.
According to an aspect of the present invention, a color bar in which three colors are expressed in three segments, is formed on the light valve.
According to still another aspect of the present invention, there is provided a projection system to display an image on a screen, including a light source radiating a single white light; a spiral lens disc including cylindrical lens cells arranged in a spiral shape and separating the single white light incident from the light source into a multi light by converting a rotational motion of the cylindrical lens cells into a rectilinear movement of a cylindrical lens array; a spectroscope separating the multi light incident from the spiral lens disc into color light beams having different wavelengths; a color splitting filter splitting the color light beams incident from the spiral lens disc into two optical paths depending on wavelengths; first and second light valves modulating the color light beams, incident via two optical paths, according to an image signal to form the image; and a projection lens projecting the color light beams modulated by the first and second light valves onto the screen to display the image.
Here, the projection system further includes a fly-eye lens on a first optical path between the spectroscope and the color splitting filter.
According to an aspect of the present invention, the projection system further includes a relay lens on a second optical path between the fly-eye lens and the color splitting filter to focus the incident light onto the light valve.
According to an aspect of the present invention, the spectroscope is a dichroic filter array to separate the incident light into the color light beams, and the dichroic filter array includes dichroic filters to separate the incident light into the color light beams
According to an aspect of the present invention, a color bar, in which one color is one segment, is formed on the first light valve, and a color bar, in which two colors are two segments, respectively, is formed on the second light valve.
According to still another aspect of the present invention, there is provided a projection system to display an image on a screen, including a light source radiating a single white light; a color splitting filter splitting the single white light incident from the light source into two optical paths depending on wavelength bands; a spiral lens disc disposed on one of the two optical paths, and including cylindrical lens cells arranged in a spiral shape, and separating the light incident from the color splitting filter into a multi light by converting a rotational motion of the cylindrical lens cells into a rectilinear movement of a cylindrical lens array; a spectroscope separating the multi light incident from the spiral lens disc into color light beams having different wavelengths; first and second light valves modulating the light, incident via two optical paths, according to an image signal in order to form the image; and a projection lens, projecting the color light beams modulated by the first and second light valves onto the screen to display the image.
According to an aspect of the present invention, the projection system further includes a fly-eye lens on a first optical path between the spectroscope and the second light valve.
According to an aspect of the present invention, the projection system further includes a relay lens on a second optical path between the color splitting filter and the light valve to focus the light on the light valve.
According to an aspect of the present invention, the spectroscope is a dichroic filter array to separate the incident light into the color light beams, and the dichroic filter array to separate the incident light into the color light beams.
According to an aspect of the present invention, a color bar, in which one color is one segment, is formed on the first light valve, and a color bar, in which two colors are two segments, respectively, is formed on the second light valve.
Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description; or may be learned by practice of the invention.